JP2020090024A - Tire vulcanizing apparatus - Google Patents

Abstract

To provide a tire vulcanizing device that appropriately vulcanizes a sidewall part.SOLUTION: In a tire vulcanizing apparatus 1 including a side mold 7U, 7L having a side molding surface 15, and a heating part J1 for heating the side mold 7U, 7L to vulcanize a raw tire Ta in contact with the side molding surface 15, the side molding surface 15 has a maximum width position M that projects most outward in an axial direction of the raw tire Ta, and the side molds 7U, 7L include a first flow path 18 in which a first fluid R1 having a temperature lower than a vulcanization temperature flows. The first flow path 18 extends in a circumferential direction of the raw tire Ta, and is located inside and outside the maximum width position M in a radial direction of the raw tire Ta, and within 20% of the sidewall height, which is a length in the tire radial direction from a bead baseline of the tire to a tread end. A temperature of the first fluid R1 is 100 to 160°C.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tire vulcanizing apparatus for vulcanizing and molding a raw tire.

The following Patent Document 1 describes a tire vulcanizing apparatus including a side mold and a heating unit for vulcanizing a raw tire. The heating unit heats the side mold to vulcanize the sidewall portion of the green tire. The side mold has a side molding surface for molding the outer surface of the sidewall portion of the tire, and has a flow path to which the first fluid having a temperature lower than the vulcanization temperature of the raw tire is supplied. Since such a flow path blocks a part of the heat generated in the heating section without transferring the heat to the sidewall section, overvulcanization of the sidewall section having a small thickness can be suppressed.

JP, 2017-71153, A

However, the inventors have found that such a tire vulcanizing apparatus also has room for further appropriately vulcanizing the sidewall portion.

The present invention has been devised in view of the above circumstances, and its main object is to provide a tire vulcanizing apparatus capable of appropriately vulcanizing the sidewall portion.

The present invention relates to a tire vulcanization including a side mold having a side molding surface for molding an outer surface of a sidewall portion of a tire, and a heating unit for heating the side mold to vulcanize a raw tire in contact with the side molding surface. In the device, the side molding surface has a maximum width position that projects most outward in the axial direction of the raw tire, and the side mold has a first temperature lower than a vulcanization temperature of the raw tire. A first flow path through which a fluid flows, wherein the first flow path has a length in a tire radial direction from a bead baseline of the tire to a tread end inward and outward in a radial direction of the raw tire from the maximum width position. The position within 20% of a certain sidewall height extends in the circumferential direction of the green tire, and the temperature of the first fluid is 100 to 160°C.

In the tire vulcanizing apparatus according to the present invention, it is preferable that the first flow path has a minimum axial distance from the side molding surface of the green tire of 5 to 15 mm.

In the tire vulcanizing apparatus according to the present invention, it is desirable that the circle-equivalent diameter of the first flow path is 10% to 30% of the sidewall height.

In the tire vulcanizing apparatus according to the present invention, it is desirable that the first flow path has a circular cross section.

In the tire vulcanizing apparatus according to the present invention, the pressure of the first fluid in the first flow path is preferably 0.1 to 1.0 MPa.

In the tire vulcanizing apparatus according to the present invention, the first fluid is preferably water or oil.

The tire vulcanizing apparatus of the present invention is a tire vulcanizing apparatus including a side mold having a side molding surface and a heating unit that heats the side mold to vulcanize a raw tire. The side mold includes a first flow path in which a first fluid having a temperature lower than the vulcanization temperature of the green tire flows. The first flow path extends inward and outward in the radial direction of the raw tire from the maximum width position, and within a position within 20% of the sidewall height in the circumferential direction of the raw tire. The temperature of the first fluid is 100 to 160°C. As a result, generally, the sidewall portion having a small rubber thickness can be appropriately vulcanized. A tire manufactured by such a tire vulcanizing apparatus has an excellent rolling resistance performance because, for example, an increase in the loss tangent of the sidewall portion is suppressed.

It is a side sectional view of a tire vulcanizer showing one embodiment of the present invention. It is an enlarged view of the tire vulcanizer of FIG. It is the sectional view on the AA line of the side mold of FIG. It is an enlarged view of the side mold of FIG. It is sectional drawing of one Embodiment of the tire after vulcanization. It is sectional drawing of the side mold of other embodiment.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a side sectional view of an entire tire vulcanizing apparatus (hereinafter, may be simply referred to as “vulcanizing apparatus”) 1 of the present embodiment. FIG. 2 is an enlarged view of the left half of the vulcanizing apparatus 1 of FIG. As shown in FIGS. 1 and 2, the vulcanization apparatus 1 is configured to include a vulcanization mold 2 and a bladder section 3. The vulcanization apparatus 1 of the present embodiment is configured such that the unvulcanized raw tire Ta mounted in the vulcanization die 2 is heated outside from the vulcanization die 2 and the tire inner surface Ti of the raw tire Ta. Is heated by the bladder portion 3 and heated internally. As a result, the raw tire Ta is vulcanized.

The vulcanization mold 2 includes a lower mold part 2L attached to the lower plate 4 and an upper mold part 2U attached to the upper plate 5 which can be moved up and down. The lower plate 4 is supported by, for example, a table base (not shown) of a press machine or the like. The upper plate 5 is attached to an elevator (not shown), and can move up and down relatively with respect to the lower mold part 2U.

The lower mold portion 2L includes a lower bead ring 6L that molds a lower bead portion of the raw tire Ta and a lower side mold 7L that molds a lower sidewall portion of the raw tire Ta. .. In addition, in this specification, "lower side" means the lower plate 4 side of the vulcanization apparatus 1, and "upper side" means the upper plate 5 side of the vulcanization apparatus 1.

The upper mold portion 2U includes an upper bead ring 6U for molding an upper bead portion of the raw tire Ta, an upper side mold 7U for molding an upper sidewall portion of the raw tire Ta, and a tread of the raw tire Ta. And a tread mold 8 for molding the portion.

In this embodiment, the lower side mold 7L is attached adjacent to the lower platen 9L fixed to the lower plate 4. The upper side mold 7U is attached adjacent to the upper platen 9U supported by the upper plate 5. The upper and lower platens 9U and 9L may be attached to the upper and lower side molds 7U and 7L via plates (not shown), respectively.

The upper and lower platens 9U and 9L of the present embodiment each include a first heating unit J1 that heats the sidewall portion of the raw tire Ta. When the first heating portion J1 is heated, heat is transferred from the upper and lower platens 9U and 9L to the upper and lower side molds 7U and 7L, and the sidewall portion of the raw tire Ta is vulcanized.

In the present embodiment, the first heating unit J1 is a steam jacket that uses steam (saturated steam) as a heating medium. In the present embodiment, for example, steam is supplied to the first heating unit J1 from a known heating medium supply source (not shown) such as a boiler provided outside the vulcanizer 1. As such steam, one having a high temperature and high pressure of 0.5 to 2.5 MPa at 180 to 220° C. is desirable. The first heating unit J1 is not limited to the one that is heated by steam, and may be heated by, for example, an electric heater.

Each of the upper and lower side molds 7U and 7L includes a side molding surface 15 that forms the outer surface of the sidewall portion of the tire T and a non-molding surface 16 that faces the opposite side of the side molding surface 15. That is, the side molding surface 15 is a portion that comes into contact with the sidewall portion of the green tire Ta during vulcanization molding. The non-molding surface 16 is a portion that contacts the raw tire Ta and contacts the upper platen 9U or the lower platen 9L during vulcanization molding. The material of the upper and lower side molds 7U, 7L is not particularly limited, but, for example, stainless steel, iron, aluminum, copper or the like is preferable.

In the present embodiment, the side molding surface 15 has a maximum width position M that projects most outward in the axial direction of the raw tire Ta. Generally, the maximum width position M is a position where a portion of the sidewall portion of the raw tire Ta where the rubber thickness is relatively small contacts.

A first flow path 18 through which the first fluid R1 flows is embedded in each of the upper and lower side molds 7U and 7L. The first fluid R1 has a temperature lower than the vulcanization temperature of the raw tire Ta. The first flow path 18 blocks a part of the heat generated in the first heating section J1 from each of the side molds 7U and 7L without transferring the heat to the sidewall portion of the green tire Ta.

FIG. 3 is a cross-sectional view of the side molds 7U and 7L of FIG. 1 taken along the line AA. As shown in FIG. 3, the first flow path 18 includes a supply side portion 18a, a discharge side portion 18b, and a main portion 18c. The supply side portion 18a is a portion where the first fluid R1 is supplied to each of the side molds 7U and 7L. The discharge side portion 18b is a portion where the first fluid R1 is discharged from each of the side molds 7U and 7L. In this way, the first fluid R1 that has acquired the heat of the first heating unit J1 is discharged from the discharge side portion 18b, so that the temperature rise in the first flow path 18 is suppressed. The main portion 18c is a portion that joins the supply side portion 18a and the discharge side portion 18b and is largely formed by each of the side molds 7U and 7L. The main portion 18c extends, for example, so as to form approximately one turn of each of the side molds 7U and 7L. Such a first flow path 18 suppresses over-vulcanization of the sidewall portion over the circumferential direction of the raw tire Ta. The first fluid R1 circulates, for example, between the supply device S provided outside the vulcanization device 1 and the first flow path 18.

The 1st flow path 18 of this embodiment is embedded in each side mold 7U and 7L. Since such a first flow path 18 is arranged at a position close to the first heating part J1, the heat can be effectively blocked and discharged.

FIG. 4 is an enlarged view of the side molds 7U and 7L of FIG. As shown in FIG. 4, in the present embodiment, the main portion 18c of the first flow path 18 has a sidewall height h (shown in FIG. 5) inside and outside the maximum width position M in the radial direction of the raw tire Ta. 20% of the position k extends in the circumferential direction of the raw tire Ta. As a result, it is possible to effectively suppress overvulcanization of a portion having a small rubber thickness. The position k is the distance in the tire radial direction between the maximum width position M and the center c1 of the main portion 18c.

FIG. 5 is a cross-sectional view of the right half of the tire T after vulcanization. As shown in FIG. 5, the “sidewall height h” is the length in the tire radial direction from the bead base line BL of the tire T after vulcanization to the tread end Te in this specification. The "bead base line BL" is a tire axial direction line that passes through the rim diameter position defined by the JATMA standard. The “tread end Te” means the outermost ground contact position in the axial direction of the tire T when a normal load is applied to the tire T in a normal state and the tire T is grounded on a plane at a camber angle of 0 degree.

The "regular state" is an unloaded state in which the tire T is assembled on a regular rim (not shown) and filled with a regular internal pressure. The "regular rim" is a rim that is defined for each tire in the standard system including the standard on which the tire T is based. For example, JATMA is a standard rim, TRA is "Design Rim", ETRTO. If so, it is "Measuring Rim". The "regular internal pressure" is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire T is based, and is the maximum air pressure for JATMA and the table "TIRE LOAD LIMITS" for TRA. The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES" is "INFLATION PRESSURE" for ETRTO.

The first fluid R1 is supplied to each of the side molds 7U and 7L at 100 to 160°C. Thereby, the sidewall portion of the green tire Ta having a small thickness can be appropriately vulcanized. Therefore, the tire T manufactured by the vulcanizing apparatus 1 of the present embodiment has an excellent rolling resistance performance because, for example, an increase in the loss tangent of the sidewall portion is suppressed.

The first fluid R1 is preferably 0.1 to 1.0 MPa. In addition, the first fluid R1 is preferably water or oil. Since such a first fluid R1 exists as a liquid, it has a high thermal conductivity. Further, the first fluid R1 can prevent the side molds 7U and 7L from being corroded by rust. The first flow path 18 may be formed of a pipe made of a material having high corrosion resistance in order to suppress the corrosion caused by the first fluid R1.

As shown in FIG. 4, in the first flow path 18, it is desirable that the minimum axial distance L1 of the raw tire Ta from the side molding surface 15 is 5 to 15 mm. If the minimum distance L1 exceeds 15 mm, there is a possibility that heat transfer to the sidewall portion of the raw tire Ta cannot be effectively blocked. If the minimum distance L1 is less than 5 mm, the durability performance of the side molds 7U and 7L may deteriorate. The distance L1 is the axial length of the raw tire Ta between the side molding surface 15 and the position of the first flow path 18 closest to the side molding surface 15.

It is desirable that the main section 18c of the first flow path 18 has a circular cross section. Accordingly, the first fluid R1 can effectively absorb the heat in the side molds 7U and 7L. The cross section of the main portion 18c of the first flow path 18 is not limited to the circular shape, and may be an elliptical shape or a rectangular shape.

In order to effectively exhibit the above-mentioned effects, the equivalent circle diameter d of the first flow path 18 is preferably 10% to 30% of the sidewall height h. If the circle-equivalent diameter d of the first flow path 18 is less than 10% of the sidewall height h, overvulcanization of the sidewall portion of the raw tire Ta may not be suppressed. If the equivalent circle diameter d of the first flow path 18 exceeds 30% of the sidewall height h, the sidewall portion of the green tire Ta may be in an unvulcanized state. In the present specification, the “circle equivalent diameter d” is the diameter of a perfect circle corresponding to the area of the cross section of the first flow path 18.

The first fluid R1 in the first flow path 18 is not particularly limited, but it is desirable that the first fluid R1 is a turbulent flow having a Reynolds number of 5000 or more. As a result, the first fluid R1 can effectively acquire the heat of each side mold 7U, 7L.

As shown in FIGS. 1 and 2, the tread mold 8 is supported by an actuator 11 attached to the upper plate 5 so as to be vertically movable. The tread mold 8 is composed of a plurality of divided segments 8A divided in the tire circumferential direction. Due to the lowering of the actuator 11, the adjacent divided segments 8A are brought into a reduced diameter state Y1 (shown in FIG. 1) in which they are joined to each other and united in an annular shape. In addition, as the actuator 11 rises, the tread mold 8 enters the expanded diameter state Y2 (shown in FIG. 2) in which the divided segments 8A move radially outward (to the actuator 11 side) and separate from each other.

The actuator 11 is, for example, an annular body that surrounds the tread mold 8 and is arranged concentrically with the axis c of the vulcanization mold 2. The actuator 11 includes a second heating unit J2 that heats the tread portion of the raw tire Ta. When the second heating portion J2 is heated, heat is transferred from the actuator 11 to the tread mold 8 and the tread portion of the raw tire Ta is heated. The second heating unit J2 is supplied from, for example, the same heating medium supply source (not shown) as the first heating unit J1. In addition, the 2nd heating part J2 is not limited to such a mode.

The bladder portion 3 is arranged at the center of the vulcanization mold 2. The bladder portion 3 of this embodiment includes a rubber bladder 12, a center post 13, a lower clamp ring 14L, an upper clamp ring 14U, and a second flow path 22. The center post 13 extends, for example, from the lower plate 4 to the upper side and is provided on the axis c of the vulcanization mold 2. The lower clamp ring 14L holds, for example, the lower opening of the rubber bladder 12 and is attached to the lower end side of the center post 13. The upper clamp ring 14U holds the upper opening of the rubber bladder 12 and is attached to the upper end side of the center post 13, for example. The second flow path 22 can communicate with the internal space of the rubber bladder 12 and supply and discharge the second fluid R2 that expands the rubber bladder 12, for example. The rubber bladder 12, the center post 13, the lower clamp ring 14L, the upper clamp ring 14U, and the second flow path 22 are each formed in a known structure in the present embodiment.

FIG. 6 is a cross-sectional view showing another embodiment of the upper and lower side molds 7U and 7L. The same components as those shown in FIGS. 1 to 4 are designated by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 6, in this embodiment, the main portion 18c of the first flow path 18 provided in the upper and lower side molds 7U, 7L is formed of the forward portion 20a, the return portion 20b, and the folded portion 20c. ing. The first fluid R1 flows toward the one side in the circumferential direction (clockwise in the drawing) in the going portion 20a of the present embodiment. In the return section 20b of the present embodiment, the first fluid R1 flows toward the other side in the circumferential direction (counterclockwise in the figure). The folding|returning part 20c of this embodiment is formed in the U shape which joins the going part 20a and the returning part 20b. In such a main portion 18c, the average of the temperatures of the going portion 20a and the returning portion 20b is the same at each circumferential position of the raw tire Ta. For this reason, the vulcanized state of the sidewall portion of the green tire Ta can be made uniform in the circumferential direction, so that, for example, the tire T having excellent rolling performance can be manufactured.

In order to effectively exhibit the above-mentioned effects, it is desirable that the forward part 20a and the return part 20b are formed concentrically with the axis c of the vulcanization mold 2.

Next, a method for vulcanizing the green tire Ta using the vulcanizing apparatus 1 shown in FIGS. 1 to 4 will be described.

First, the raw tire Ta is set at a predetermined position of the vulcanization apparatus 1, and the upper and lower mold parts 2U and 2U are closed by the elevator (not shown).

Next, for example, steam is supplied to the first heating unit J1 and the second heating unit J2 from the heating medium supply source (not shown), and the upper and lower bead rings 6U and 6L, the upper and lower side molds 7U and 7L, and the tread. The mold 8 is heated. The steam is controlled to 0.5 to 2.5 MPa at 180 to 220° C., for example.

Next, the first fluid R1 is supplied from the supply device S to the first flow path 18. The first fluid R1 is, for example, water or oil. The first fluid R1 is controlled at 100 to 160° C., for example. The first fluid R1 is controlled to have a pressure of 0.1 to 1.0 MPa, for example. The first flow path 18 is arranged at the position as described above. Thereby, the sidewall portion of the raw tire Ta having a small rubber thickness can be appropriately vulcanized.

Although the tire vulcanizing apparatus of the present invention has been described above in detail, the present invention is not limited to the specific embodiments described above and may be carried out in various modes.

Pneumatic tires for passenger cars were prototyped using the tire vulcanizing apparatus of FIG. 1, and the loss tangent and rolling resistance performance of each test tire was tested. The common specifications and test methods for each sample tire are as follows. Except for the specifications listed in Table 1, the specifications of each example and each comparative example are the same.
Tire size: 215/45R17
Temperature in the first heating part and temperature in the second heating part: 200°C
The vulcanizer of Comparative Example 1 is not provided with the first flow path.

<Loss tangent (tan δ)>
Using a viscoelastic spectrometer, the loss tangent of the sidewall rubber of the sidewall portion of the test tire was measured under the following conditions in accordance with JIS-K6394. The result is displayed as an index with the difference between the measured value of Comparative Example 1 and the target value of the loss tangent being 100. The smaller the number, the better. The target value of the loss tangent is the same in any of the comparative examples and the examples.
Initial strain: 10%
Amplitude: ±2%
Frequency: 10Hz
Deformation mode: Tensile Measurement temperature: 70℃

<Rolling resistance performance>
Using a rolling resistance tester, the rolling resistance of the test tire was measured under the following conditions. The result is displayed as an index with the value of Comparative Example 1 being 100. The smaller the value, the smaller the rolling resistance and the better.
Rim: 15×6JJ
Internal pressure: 230kPa
Load: 3.43kN
Speed: 80km/h

As a result of the test, it is understood that the tires of Examples are closer to the target value of loss tangent and are excellent in rolling resistance performance than the tires of Comparative Examples.

1 Tire Vulcanizing Device 7 Side Mold 15 Side Molding Surface 18 First Flow Path BL Bead Baseline J1 Heating Part h Sidewall Height M Maximum Width Position R1 First Fluid T Tire Ta Raw Tire Te Tread End

Claims (6)

A tire vulcanizing apparatus comprising: a side mold having a side molding surface for molding an outer surface of a sidewall portion of a tire; and a heating unit for heating the side mold to vulcanize a raw tire in contact with the side molding surface. ,
The side molding surface has a maximum width position that protrudes most outward in the axial direction of the raw tire,
The side mold includes a first flow path in which a first fluid having a temperature lower than the vulcanization temperature of the green tire flows.
The first flow path is within 20% of the sidewall height, which is the length in the tire radial direction from the bead baseline of the tire to the tread end, inward and outward in the radial direction of the raw tire from the maximum width position. A position extends in the circumferential direction of the raw tire,
The temperature of the first fluid is 100 to 160° C.,
Tire vulcanizer. The tire vulcanizing device according to claim 1, wherein the first flow path has a minimum axial distance of the green tire from the side molding surface of 5 to 15 mm. The tire vulcanizing apparatus according to claim 1 or 2, wherein a circle-equivalent diameter of the first flow path is 10% to 30% of the sidewall height. The tire vulcanizing apparatus according to claim 1, wherein a cross section of the first flow path has a circular shape. The tire vulcanizing apparatus according to claim 1, wherein the pressure of the first fluid in the first flow path is 0.1 to 1.0 MPa. The tire vulcanizing apparatus according to claim 1, wherein the first fluid is water or oil.

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